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Water system · PWSID CA1500465

OAK KNOLLS MUTUAL WATER COMPANY

LAKE ISABELLA, CA · ~123 people served

Check your exact address → LAKE ISABELLA overview
85
Excellent
PurityRadar safety score

PWSID

CA1500465

State

California

City

LAKE ISABELLA

Population served

123

Primary source

Groundwater

Score history

No change since tracking began Jun 18, 2026.

Jun 18, 2026 · score 85 Jun 18, 2026 · score 85

2 score updates logged since tracking began Jun 18, 2026. Each future EPA re-score adds a point.

PFAS & contaminant readings

No PFAS detections are on record for this system from EPA’s UCMR5 monitoring (2023–25). Absence of a detection isn’t a guarantee — not every system was sampled, and this dataset doesn’t cover other contaminants.

Violations & enforcement

16

Violations on record

2

Unaddressed

5

Health-based

18

Enforcement actions

From EPA ECHO (SDWIS), most recent enforcement Aug 2024. Official EPA record →

Reporting · EPA contaminant 5200 began Oct 2024 Unaddressed
Treatment technique · EPA contaminant 5200 health-based began Oct 2024 Unaddressed
Max contaminant level (MCL) · Nitrate health-based began Jan 2025 Resolved
Max contaminant level (MCL) · Nitrate health-based began Oct 2024 Resolved
Max contaminant level (MCL) · Nitrate health-based began Jul 2024 Resolved
Max contaminant level (MCL) · Total coliform health-based began Mar 2012 Resolved
Other · EPA contaminant 7000 began Jul 2008 Resolved
Other · EPA contaminant 7000 began Jul 2007 Resolved
Monitoring & reporting · Total coliform began Apr 1998 Resolved
Monitoring & reporting · Nitrate began Jan 1997 Resolved
Monitoring & reporting · Lead & Copper Rule began Jul 1996 Resolved
Monitoring & reporting · Lead & Copper Rule began Jan 1996 Resolved

Recent enforcement actions

  • State action · SFL Aug 2024
  • State action · SOX Mar 2018
  • State action · SIA Aug 2013
  • State action · SOX Aug 2013
  • State action · SFL May 2013
  • State action · SOX Apr 2012
  • State action · SFL Mar 2009
  • State action · SFL Jun 2008

This profile is built from EPA public records for system CA1500465 — SDWIS violations and UCMR5 PFAS sampling. The score is system-level and can’t account for your home’s plumbing (older pipes can add lead at the tap). For health decisions, check your exact address, read the utility’s Consumer Confidence Report, and confirm with your provider.